class MayBe {
  static of(value) {
    return new MayBe(value);
  }

  constructor(value) {
    this._value = value;
  }

  map(fn) {
    return this.isNothing() ? MayBe.of(null) : MayBe.of(fn(this._value));
  }

  isNothing() {
    return this._value === null || this._value === undefined;
  }
}

class Container {
  static of(value) {
    return new Container(value);
  }

  constructor(value) {
    this._value = value;
  }

  map(fn) {
    return Container.of(fn(this._value));
  }
}

module.exports = {
  Maybe: MayBe,
  Container: Container,
};
